Conventionally, a reflection characteristic measuring device that measures a reflection characteristic has been known. Examples of the reflection characteristic include, for example, a spectral reflectance, a gloss value, brilliance, and the like. The spectral reflectance is a reflectance for each wavelength. The gloss value is a numerical value that represents a degree of glossiness, and is obtained according to a ratio between intensity of specular reflection light and intensity of scattered reflection light. The brilliance is a numerical value representing a glittering appearance caused by a brightening agent (such as aluminum flake) included in a metallic paint, a pearl paint, and the like. Those various reflection characteristics are defined by, for example, standards and the like, and there is geometry suitable for the measurement. For example, the spectral reflectance is measured using geometry such as 45° illumination/0° reception, 45° illumination/multi-angle reception, and diffuse illumination/8° reception. Further, for example, the gloss value is measured using geometry of 20° gloss (20° illumination/20° reception), 60° gloss (60° illumination/60° reception), and 85° gloss (85° illumination/85° reception). Therefore, conventionally, in general, the spectral reflectance has been measured by, for example, a spectroscope for spectral reflectance measurement, the gloss value has been measured by, for example, a glossmeter for gloss measurement, and the brilliance has been measured by a measuring device for brilliance measurement. In recent years, for example, as disclosed in Patent Literature 1, those plurality of measuring devices is integrated into one measuring device, and a device capable of measuring a plurality of types of reflection characteristics with respect to the same part of an object of measurement, which is an object to be measured, has been developed.
Meanwhile, for the measurement of the reflection characteristic, there is measurement using a diffuse reflecting member having a diffuse reflecting surface that performs diffuse reflection such as an integrating sphere. For example, in a case where the spectral reflectance is measured using the geometry of diffuse illumination/8° reception, an integrating sphere is used to generate the diffuse illumination. As described above, in a case where the plurality of measuring devices is integrated into one measuring device, the integrated measuring device includes a plurality of geometries to make it possible to measure a plurality of types of reflection characteristics. As a result, there may be a case where the integrated measuring device is provided with a geometry including the diffuse reflecting member (first geometry) as necessary for the measurement, and a geometry not including the diffuse reflecting member (second geometry) unnecessary for the measurement. In such a case, at the time of measuring using the second geometry, the light in the second geometry is diffusely reflected by the diffuse reflecting surface of the first geometry, and the diffusely reflected light and the light caused by the diffused light may be measured using the second geometry at times, which results in a measurement error. As an example, in a case where the geometry of diffuse illumination/8° reception and the geometry of 60° gloss (60° illumination/60° reception) are integrated, while the illumination light in the geometry of 60° gloss is reflected by a surface of the object to be measured and most of the reflected light is received and measured by a light receiving part in the geometry of 60° gloss, a part of the reflected light is made incident on the integrating sphere in the geometry of diffuse illumination/8° reception. For example, the reflected light is roughly divided into surface reflected light having been subject to Fresnel reflection on the surface and internal diffuse reflected light that once penetrates into the object to be measured, being absorbed by the object to be measured, for example, and then being emitted from the surface. The surface reflected light is scattered due to surface roughness of the object to be measured, and light having an angle larger than an acceptance angle range at the geometry of 60° gloss is made incident on the integrating sphere. Most of the internal diffuse reflected light is made incident on the integrating sphere. The light having been incident on the integrating sphere repeats irregular reflection in the integrating sphere, and a part of the light illuminates the object to be measured (recursive diffused illumination). The light based on the recursive diffused illumination acts on the object to be measured in a similar manner to the illumination light in the geometry of 60° gloss described above. As a result, a part of the light is received by the light receiving part in the geometry of 60° gloss, which results in a measurement error.